Here is the full list of all 18 Ion Assault achievements.
Score exceeds 5,000,000 points (Campaign).
Score exceeds 3,000,000 points (Campaign).
Get two extra-lives with a single score upload.
Score exceeds 10,000,000 points (Survival).
Score exceeds 5,000,000 points (Survival).
Score exceeds 2,500,000 points (Survival).
Score exceeds 1,000,000 points (Survival).
Score exceeds 500,000 points (Survival).
Destroy seven asteroids at once.
Complete a whole sector without dying once.
Finished a stage in less than 90 seconds.
Completed the single player campaign.
Score exceeds 1,500,000 points (Campaign).
Destroy five asteroids at once.
Score exceeds 500,000 points (Campaign).
Survive 3 stages in a row without losing a life.
Destroy 50 big asteroids in a single game.
Complete a regular stage without collecting a single Power-Up.